/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.graphics;

import android.content.Context;
import android.graphics.*;
import android.os.Bundle;
import android.view.View;

public class Regions extends GraphicsActivity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {
		private final Paint mPaint = new Paint();
		private final Rect mRect1 = new Rect();
		private final Rect mRect2 = new Rect();

		public SampleView(Context context) {
			super(context);
			setFocusable(true);

			mPaint.setAntiAlias(true);
			mPaint.setTextSize(16);
			mPaint.setTextAlign(Paint.Align.CENTER);

			mRect1.set(10, 10, 100, 80);
			mRect2.set(50, 50, 130, 110);
		}

		private void drawOriginalRects(Canvas canvas, int alpha) {
			mPaint.setStyle(Paint.Style.STROKE);
			mPaint.setColor(Color.RED);
			mPaint.setAlpha(alpha);
			drawCentered(canvas, mRect1, mPaint);
			mPaint.setColor(Color.BLUE);
			mPaint.setAlpha(alpha);
			drawCentered(canvas, mRect2, mPaint);

			// restore style
			mPaint.setStyle(Paint.Style.FILL);
		}

		private void drawRgn(Canvas canvas, int color, String str, Region.Op op) {
			if (str != null) {
				mPaint.setColor(Color.BLACK);
				canvas.drawText(str, 80, 24, mPaint);
			}

			Region rgn = new Region();
			rgn.set(mRect1);
			rgn.op(mRect2, op);

			mPaint.setColor(color);
			RegionIterator iter = new RegionIterator(rgn);
			Rect r = new Rect();

			canvas.translate(0, 30);
			mPaint.setColor(color);
			while (iter.next(r)) {
				canvas.drawRect(r, mPaint);
			}
			drawOriginalRects(canvas, 0x80);
		}

		private static void drawCentered(Canvas c, Rect r, Paint p) {
			float inset = p.getStrokeWidth() * 0.5f;
			if (inset == 0) { // catch hairlines
				inset = 0.5f;
			}
			c.drawRect(r.left + inset, r.top + inset, r.right - inset, r.bottom
					- inset, p);
		}

		@Override
		protected void onDraw(Canvas canvas) {
			canvas.drawColor(Color.GRAY);

			canvas.save();
			canvas.translate(80, 5);
			drawOriginalRects(canvas, 0xFF);
			canvas.restore();

			mPaint.setStyle(Paint.Style.FILL);

			canvas.save();
			canvas.translate(0, 140);
			drawRgn(canvas, Color.RED, "Union", Region.Op.UNION);
			canvas.restore();

			canvas.save();
			canvas.translate(0, 280);
			drawRgn(canvas, Color.BLUE, "Xor", Region.Op.XOR);
			canvas.restore();

			canvas.save();
			canvas.translate(160, 140);
			drawRgn(canvas, Color.GREEN, "Difference", Region.Op.DIFFERENCE);
			canvas.restore();

			canvas.save();
			canvas.translate(160, 280);
			drawRgn(canvas, Color.WHITE, "Intersect", Region.Op.INTERSECT);
			canvas.restore();
		}
	}
}
